Intra-individual variability over time in serum cytokine levels among participants in the prostate, lung, colorectal, and ovarian cancer screening Trial.

Abstract

BACKGROUND:

Serum measurements of cytokines, mediators of various B and T cell activities, are important markers of inflammation and immune dysregulation. We assessed the reproducibility of serum cytokine measurements over a five-year period among participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO).

METHODS:

Levels of 13 cytokines [interleukin (IL) 1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, interferon-gamma (IFNγ), granulocyte macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-α (TNFα)] in stored sera from three collections (study baseline,+1 year, and+5 years) among 28 randomly selected PLCO participants were measured using a high-sensitivity Luminex xMap-based multiplex panel. Within- and between-subject components of variance were estimated from random effects models and were used to calculate the coefficient of variation (CV) and intraclass correlation coefficient (ICC) for analytes with <30% of samples below the limit of detection (LOD). Spearman correlation coefficients between measurements of the same analyte over time and between analytes were also calculated.

RESULTS:

Among the six cytokines with <30% of samples below the LOD, we observed excellent reproducibility for IL-6, IL-7, IL-13, and TNFα (ICC≥0.73), and fair to good reproducibility for IL-8 (ICC=0.55) and IL-10 (ICC=0.60). Spearman correlation coefficients comparing paired measurements of each cytokine at baseline and at +5 years were high (ρ≥0.74) with the exception of IL-10 (ρ=0.44).

CONCLUSIONS:

These results suggest that measurements of most of the cytokines evaluated in this study were highly reproducible over five-year periods.

• Authors: Jonathan N Hofmann, Kai Yu, Rachel K Bagni, Qing Lan, Nathaniel Rothman, Mark P Purdue
• Journal: Cytokine (Cytokine) Vol. 56 Issue 2 Pg. 145-8 (Nov 2011) ISSN: 1096-0023 [Electronic] England
• PMID: 21764327 (Publication Type: Journal Article, Research Support, N.I.H., Intramural, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: Published by Elsevier Ltd.

Chemical References

• Cytokines

Topics

• Aged
• Colorectal Neoplasms (blood, diagnosis)
• Cytokines (blood)
• Female
• Humans
• Limit of Detection
• Lung Neoplasms (blood, diagnosis)
• Male
• Middle Aged
• Ovarian Neoplasms (blood, diagnosis)
• Prostatic Neoplasms (blood, diagnosis)